Antimicrobial effects of an antiperspirant formulation containing aqueous aluminum chloride hexahydrate

To document deodorant efficacy the antimicrobial activity of a gelatinous antiperspirant formulation of aqueous aluminum chloride hexahydrate was investigated. In vitro assays demonstrated highly bactericidal activity on microorganisms comprising the resident axillary skin flora, including micrococcaceae and aerobic diphtheroid bacteria. Gram-negative bacteria and yeast were partially inhibited. In vivo experiments utilizing occlusive patches on forearm skin and bacterial sampling of the axilla showed pronounced bacteriostasis and persistence of aluminum chloride on the skin. Inhibition of microbial growth lasted more than 3 days after a single treatment of the axilla. Following repeated open applications to the volar aspect of the forearm, the skin remained virtually sterile for 3 days.